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Solar Air Conditioner

To those who want to run it at a higher voltage (48v, for instance) just add one of these to your order:


Most "mini-split inverter air conditioners" on the market run internally on 48v. Aliexpress is full of them as "solar air conditioners". The are just leaving out the convert alternating current to DC part (or maybe not).

They do substantially reduce surge startup.
 
Higher voltage benefit comes from the reduction in the Ohmic loss. I2R transmission power loss requires a thicker gauge wires and protection for the lower DC voltage. As you pointed out, most DC air conditioner uses a brushless DC motor so you don't need an inverter. Less startup surge has to do with the DC motor frequency control while conventional alternating current brush motor turns on and off with the huge surge in current.
 
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In my humble opinion, Aliexpress is nothing but outsourcing Amazon out of our country. People don't like Amazon for many reasons and Amazon sellers hate Amazon because of the recent increase in the referral fee. However, we don't want to outsource our jobs to Alibaba. It is about economy and job security in our homeland.
 
I have been interested in this thread for a while. However most high efficiency mini split units are running 300+v inverters from the line, which is contrary to you stating they use 48v. My Midea U (a dual inverter mini split on a common pan basically) uses 310v blower motors and compressor, and amazingly achieves 15btu/w.

I have tried reaching out to Alibaba.com sellers about 24v truck units but no one will provide data sheets or efficiency ratings. Best I can figure based on the given specs is ~10btu/w much like my old 110v Frigidaire 8000btu. Start up current may be a benefit in comparison to old style window units, but for a Midea U the 10% inverter losses is < 50% efficiency gain in btu output and the Midea unit starts extremely soft too the benefits weigh in favor of the Midea. The cost of these DC direct units also blows away the cost of an efficient window unit and a capable inverter. $349 Midea 8k window unit + 200 inverter and you'll still have some wiring money left.

I would order two of these tomorrow if the efficiency could match what exists here already. I would love to pitch in and assist in bringing up something more efficient if there is interest.
 
I have been interested in this thread for a while. However most high efficiency mini split units are running 300+v inverters from the line, which is contrary to you stating they use 48v. My Midea U (a dual inverter mini split on a common pan basically) uses 310v blower motors and compressor, and amazingly achieves 15btu/w.

I have tried reaching out to Alibaba.com sellers about 24v truck units but no one will provide data sheets or efficiency ratings. Best I can figure based on the given specs is ~10btu/w much like my old 110v Frigidaire 8000btu. Start up current may be a benefit in comparison to old style window units, but for a Midea U the 10% inverter losses is < 50% efficiency gain in btu output and the Midea unit starts extremely soft too the benefits weigh in favor of the Midea. The cost of these DC direct units also blows away the cost of an efficient window unit and a capable inverter. $349 Midea 8k window unit + 200 inverter and you'll still have some wiring money left.

I would order two of these tomorrow if the efficiency could match what exists here already. I would love to pitch in and assist in bringing up something more efficient if there is interest.
Yes, and apparently the Midea U is the only thing you can find.
Most high efficiency mini splits are running 48v.


Fortunately, not me.



FYI, Mr Cool is one that runs 48v internally, Costco has them on sale right now.
 
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Yes but still the motors in the unit are ~300v as I mentioned earlier. This item also shows unavailable, and there are no efficiency specs. It also does not help me being on 24v. I would love to find a programmable inverter that could go 24v-300v dual inverter and PWM fan with good efficiency and get my Midea off my inverter. Your product has the 48v version so I hope a product like it for 24v is close.
Also want to ask, is it more efficient to buck 48v to 300v and use the higher voltage motors than use 48v motors directly? Is this something your company researched?
 
Yes but still the motors in the unit are ~300v as I mentioned earlier. This item also shows unavailable, and there are no efficiency specs. It also does not help me being on 24v. I would love to find a programmable inverter that could go 24v-300v dual inverter and PWM fan with good efficiency and get my Midea off my inverter. Your product has the 48v version so I hope a product like it for 24v is close.
Also want to ask, is it more efficient to buck 48v to 300v and use the higher voltage motors than use 48v motors directly? Is this something your company researched?

I suspect the reason you don't find many 12v and 24v systems is due to how many amps they would draw. However finding a 48v system is no problem. The 48v system I'm looking at is 18.75 amps max draw at 48v (12000 BTU mini-split). That is very easy to carry on 10 gauge wire. I haven't seen one that takes 300vdc as an input voltage.

Research? Google.
 
Long story short, ACDC 12V air conditioner was a big hit at Amazon. First batch of 30 sets was sold out in 2 weeks and second batch of 100 sets will be on line starting next week. Please check the Amazon link for the ACDC 12V air conditioner detail: https://www.amazon.com/dp/B08DHP82LG
I like your Entrepreneur spirit. Looks like you have a really good product on your hand, all you need to do is be able to mass produce them so the price can be lower.
 
I like your Entrepreneur spirit.
Me too!!


I seriously believe there’s a Big Future Everywhere in thermal management!

Thanks for researching new solutions! DC power air conditioning solutions excite me because they are Eminently Engineerable!

Even if a small battery + solar system can’t enable 24/7 operation at 100% compressor load, it can still improve the comfort of someone meaningfully!
 
I suspect the reason you don't find many 12v and 24v systems is due to how many amps they would draw. However finding a 48v system is no problem. The 48v system I'm looking at is 18.75 amps max draw at 48v (12000 BTU mini-split). That is very easy to carry on 10 gauge wire. I haven't seen one that takes 300vdc as an input voltage.

Research? Google.
There are actually plenty of inefficient 12 and 24v systems, they are made for sleeper trucks and heavy equipment.

also very simple your unit draws 900w max at 18.75a @ 48v. 24v would be twice that at 37.5A. Within capabilities of 8 gauge wire.

I'm very surprised at the efficiency of 14.4btu/watt. Impressive. Wish I had a 48v setup.
 
Higher voltage benefit comes from the reduction in the Ohmic loss. I2R transmission power loss requires a thicker gauge wires and protection for the lower DC voltage. As you pointed out, most DC air conditioner uses a brushless DC motor so you don't need an inverter. Less startup surge has to do with the DC motor frequency control while conventional alternating current brush motor turns on and off with the huge surge in current.
I have nothing but encouragement for you and your business.
It will be great to have more 12 and 24v dc choices in this market.
Personally I would like to see something under 10”(253mm) height, and preferably around 8” (200mm) if possible.
 
Sorry for bumping into an old conversation. Your business idea of developing a 12V DC air conditioner for RVs and trucks sounds fantastic. The cooling power of 6000 BTU, power consumption range, and the ability of a 12V LiFePO4 300Ah battery to sustain more than 8 hours of operation is impressive. I suggest you contact the air conditioning engineers here https://www.spartamech.co.uk/air-conditioning-service to discuss such an idea. I hope that helps!
 
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Need more than 6kbtu cooling if it’s anything but a small white van in actual hot ambient conditions.

Most MB Sprinter van or Ford Transit or Promaster based Rv’s have >12kbtu ACunits, and those vans are all insulated (some better than others).
Darker color vans definitely require much more btu’s of AC, due to heat gain.
 
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